Coreus marginatus

Abstract: The structure and function of the hemelytra-to-hindwing locking mechanism of the bug Coreus marginatus were analysed. The system consists of a cuticular protrusion in the ventral side of the hemelytra, which locks the subcostal border of the hindwing in flight. The speed and distance slid by both surfaces against one another during flight were assessed using a combination of high-speed video recordings and a 2D geometrical model. The friction coefficient between sliding surfaces was assessed using a micromanipulator, coupled with force transducers. This was done under three experimental conditions: freshly dissected, air dried and rehydrated ethanol preserved samples. The results showed a high speed of sliding, approximately 0.18 m s−1, with a relatively low friction coefficient (0.2 μ). There was no evident difference in the friction measured under the various treatments, with the exception of the rehydrated condition, which was lower. The surface morphology of the wing locking mechanism, namely outgrowths of one part having rounded edges, and completely flat surface on the counterpart, effectively aids in the reduction of friction at the microscopic level. The structure is effective even dry, and after being preserved in ethanol, suggesting that no cuticle secreted lubrication substance is responsible for its effectiveness. The ultrastructure presumably confers mechanical stability to the system under the high load it is subjected to in flight.

Abstract: Leptoglossus occidentalis Heidemann (Heteroptera: Coreidae) is a North American conifer seed pest that was accidentally introduced to Europe. In the Mediterranean area, it threatens the production of Pinus pinea Linnaeus seeds. The egg-parasitoid Gryon pennsylvanicum (Ashmead) (Hymenoptera: Platygastridae), the main natural enemy in the native range of L. occidentalis, was imported from British Columbia to Italy. Pre-release risk assessments were made under quarantine conditions by no-choice tests conducted with naive and experienced G. pennsylvanicum offering single eggs of target and non-target species for varying exposure times (1, 4, 48 h). G. pennsylvanicum successfully parasitized from 75% to 100% of the target host eggs. Only one female specimen of the egg-parasitoid emerged from a non-target egg (Gonocerus juniperi Herrich-Schaeffer, Heteroptera: Coreidae). Two dead female specimens were found, one inside an egg of Coreus marginatus (Linnaeus) (Heteroptera: Coreidae) and one in an egg of Camptopus lateralis (Germar) (Heteroptera: Alydidae). All three cases occurred at the longest oviposition exposure time. Results obtained with this conservative approach suggest that the risk to non-target species of releasing G. pennsylvanicum in Italy is low.

Abstract: Here we described a new trypanosomatid species, Phytomonas lipae, parasitizing the dock bug Coreus marginatus based on axenic culture and in vivo material Using light and electron microscopy we characterized the development of this flagellate in the intestine, hemolymph and salivary glands of its insect host The intestinal promastigotes of Phytomonas lipae do not divide and occur only in the anterior part of the midgut From there they pass into hemolymph, increasing in size, and then to salivary glands, where they actively proliferate without attachment to the host's epithelium and form infective endomastigotes We conducted molecular phylogenetic analyses based on 18s rRNA, gGAPDH and HSP83 gene sequences, of which the third marker performed the best in terms of resolving phylogenetic relationships within the genus Phytomonas Our inference demonstrated rather early origin of the lineage comprising the new species, right after that of P oxycareni, which represents the earliest known branch within the Phytomonas clade This allowed us to compare the development of P lipae and three other Phytomonas spp in their insect hosts and reconstruct the vectorial part of the life cycle of their common ancestor

Abstract: The morphology of the metathoracic scent glands of Coreus marginatus (Linnaeus, 1758) (Heteroptera: Coreidae) was studied by scanning electron microscopy. The metathoracic scent glands are composed of a reservoir and a pair of lateral glands that connect to the reservoir through a duct. The metathoracic scent glands open to the surface through paired ostioles located between the 2nd and 3rd coxae in evaporation areas with a mushroom-like structure. Extracts of the volatile fraction from male and female metathoracic gland secretions were analyzed by capillary gas chromatography-mass spectrometry (GC-MS). Thirteen and sixteen compounds were detected in males and females, respectively. Most of the chemical compounds are qualitatively similar on each male and female but they differ in their quantity. In the analyses of metathoracic scent glands of females of C. marginatus, n-hexenoic acid (22.46%) was determined at the most and 14-Beta-H-Pregna (0.12%) was determined at the least in all samples. In males, octadecanoic acid (57.78%) was determined at the most and n-hexyl acetate (0.06%) was determined at the least in all samples.